Plasma membrane electron transport complex (PMET)

The Plasma membrane electron transport (PMET) complex is a multi-component redox system located in the plasma membrane of eukaryotic cells that facilitates the transfer of electrons from intracellular donors, primarily NADH and NADPH, to extracellular acceptors (Del Principe et al., 2011). This system consists of various enzymes such as NADH-cytochrome b5 reductase, NAD(P)H:quinone oxidoreductase 1 (NQO1), and the ENOX protein family, often employing ubiquinone as a mobile electron carrier (Ly & Lawen, 2003). PMET plays a vital role in maintaining the cytosolic NAD+/NADH ratio, which is essential for sustaining glycolysis, especially in cells with impaired mitochondrial respiration (Berridge & Tan, 2000). Additionally, it is involved in the regulation of intracellular pH and the regeneration of extracellular antioxidants like vitamin C and E (Crane, 2001). In pathological states, PMET is frequently overexpressed in cancer cells to support rapid growth and survival under metabolic stress, making it a target for anti-proliferative therapies (Morré & Morré, 2011). Conversely, pharmacological activation or supplementation of this system, for instance with idebenone, is used to treat mitochondrial disorders by providing an alternative pathway for electron flow (Haefeli et al., 2011).

Other names

Trans-plasma membrane electron transportTPMETPlasma membrane redox systemPMRSPlasma membrane redox chain

Modulation of trans-plasma membrane electron flow to regulate intracellular NAD+ levels and extracellular antioxidant status.